A food sweetener called erythritol, which occurs naturally in certain fruits and is a widely used substitute for sugar, has been identified as a biomarker for increasing fat mass, according to new research.

Although erythritol, a sugar substitute used to sweeten low-calorie foods, supposedly has very little impact on blood glucose with its zero calorie content (0.2 kcal/g versus 4 kcal/g for sugar), it has now been identified as a biomarker for weight gain by a study led by Cornell University researchers and researchers at Braunschweig University of Technology, Germany, and the University of Luxembourg, Luxembourg.

Erythritol – which occurs naturally in a variety of fruits, such as pears, watermelon and grapes, fermented products like wine and miso, as well as soy sauce – could favour weight gain and an increase in fat mass, the study reports.